Tim wrote: >> 2) I also had a problem with the default gateway, >> but this is more a matter of understanding an elementary networking >> issue. I guess what I need is a short primer on networking for >> simpletons. Is there anything along those lines online? > > Have you searched the Linux documentation project website?
Thanks very much for your always useful responses. I did look around a little. The most helpful document I found was a discussion of the "packet delivery process" at <kristie.com/mark/ccna/ICND110S01L06.pdf>, >> Suppose machine A has default gateway machine B, >> and suppose machine B has default gateway machine C. >> Now suppose that on machine A I ping, or ssh to, an address not on the >> LAN. Shouldn't this go to machine B, and then automatically get forwarded >> to C? > > Theoretically, yes. So long as the netmask and IP address combinations > show that the address is foreign. And so long as IP forwarding is > enabled on all the machines the traffic goes *through* (IP forwarding is > not enabled on the client behind all the gateways). I think I got this wrong too. I am running shorewall on my server, and I forgot to turn iptables off. >> Incidentally, someone (I guess NM) keeps emptying my /etc/resolv.conf . >> However, I fill it up each time. > > Did you say how you set it? I see now I can go to Manage Connections in NM, and specify the name servers. Now NM seems to leave /etc/resolv.conf alone. Previously I was just adding the nameservers by hand. >> Incidentally, I notice that my laptop, running Fedora-15, >> seems to behave slightly differently to my desktop, running CentOS-5.6 , >> Changes to the routing table on the latter, eg changing the default >> gateway, do not seem to come into force until I re-boot. > > How are you trying to bring about the gateway change? Are you bringing > its interface down and back up again, to force a configuration reload? I was using "route delete default" and "route add default gw ...". This seemed to be recognized at once on Fedora, but not on CentOS. > To be honest, my opinion about NetworkManager is thus: You'd only use > it on clients. All servers and gateways would have manually set network > configurations, and be using the old network service. Thanks for the suggestion. I see I am running NM on the server in question. I'm never quite sure if we are allowed to use the network service. -- Timothy Murphy e-mail: gayleard /at/ eircom.net tel: +353-86-2336090, +353-1-2842366 s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland -- users mailing list users@lists.fedoraproject.org To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
